Machine and method for forming collapsible tubing



April 8, 1952 w. E. REJESK] MACHINE AND METHOD FOR FORMING COLLAPSIBLETUBING 4 Sheets-Sheet 1 Filed March 10, 1949 f'cr/nfor- WtCliarnEReieskiApril 8, 1952 w. E/REJESKI 2,592,336

I MACHINE AND METHOD FOR FORMING COLLAPSIBLE TUBING Filed March 10, 19494 Sheets-Sheet 2 2 J-CONvo CONvo April 8, 1952 w. E. REJESKI 2,592,336

MACHINE AND METHOD FOR FORMING COLLAPSIBLE TUBING Filed March 10, 1949 4Sheets-Sheet 5 g 49 6 8Q HO 6 e [Tu/M TVZQamEReiesTfc' Aprll 8, 1952 wREJESK] 2,592,336

MACHINE AND METHOD FOR FORMING COLLAPSIBLE TUBING Filed March 10, 1949 4Sheets-Sheet 4 Patented Apr. 8, 1952 UNITED .MACHINE AND METHOD FORFORMING CGLLAPSIBLE TUBING William E. 'Reje'ski, Hartford, Conn,ass'ignor to The Wiremo'ld Company, Hartford, 'Oonm, a corporation ofConnecticut Application March 10, 19.49, Serial No. 80,675

I Bil-Claims.

This invention relates to methods and machines for making tubing andmore particularly fiexible and collapsible two-element tubing.

It is an object of this invention to provide an improved method ofcombining the elements composing the tubing and thereafter forming thetubing of the combined elements in such a way that when the tubing iscollapsed, 'the'ilexible element or fabric will Ifold outwardly andhence not impede the passage of air or "fluid through the tubing as isthe case when the flexible material or fabric folds inwardly Anotherobject is to provide a machine .tior carrying out the new method and forproducing the new tubing.

Another object of the invention is to provide a machine and .method forcombining the elements of collapsible tubing in such a way astozre'quire the use of a less amount of metal than heretofore has beennecessary.

Other objects and advantages of the invention will become apparent as itis described in connection with the accompanying drawings.

'In the drawings:

Fig.1 is a fragmentary perspective view partly in section of a portionof a'machine for making the improved tubing and for carrying out mynovel method for forming theltubirig,

.Fig- 2 is a plan view partly broken away and partly in section, of amachine assh'own in Fig. 1 embodying the invention;

lFigfiB is an end view or themachine illustrated in Fig.2 but with thefabric guide removed:

'Fig. 4 is a detail view showing in bottom plan the endfp'or'tio'noithefabric'guide;

Fig. 5 is an end view or the "fabric guide illustrated in Fig. 4;

Fig. 6 *is a fragmentary "view partly-in section of the mandrel andpressure roils'acting'upon'the second and third 'convolutions of tubingbeing :formed 'accordingto'th'e invention;

Fig.6! is atop plan viewpartly in section o'fthe pressure rolls and-their adjusting mechanism associated'withtheir driving mechanism;

Fig. 8 is a transverse section view taken a'l'on'g pinching roll and'itsmountin Fig. 12 is a section 'view 'o'i'another form-of tubing whichcan be made by the invention,

"This invention is an improvement upon the machine and method disclosedin the application of A.'E. Ch'ernack, S. N.'705;O39,"filed October -23,1946, for Method and Machine 'for Forming'Tubing," Patent Number2,539,814.

' Referring to the drawings, a strip of thin sheet metal 20 whichpreferably is preformed by any "suitable means into channel shape byhaving its opposite "edges bent into acute angles to form flanges 2| and22, is fed to a rotating mandrel (designated generally by 30) and rotarybending and pinching rolls (designated generally by 45 and and is guidedin an advancing spiral path by a *guideway "42 in a'g-uide blockliL-aswill hereinafter more particularly be described.

The cylindrical mandrel 30 is formed on a 1'0- "tatin'gsha ft 28extending through the guide block 40. The mandrel 30 also extendsthrough the guide "block 48 and is held in place on the rotating shaft28 by means of a key (not shown) :and bolt 34, so as to rotate'withshaft 28.

'The guide block so is a machined casting mounted on a stationarycasting 43 which may in turn be mounted upon asu'itable machine framenot shown. 'The guide block-ln has a spiral guideway -42, rectangular incross-section, out into its vertical iac'e around and adjacent themandrel 311 to receive the tra l-ling edge 'z'z-cr the-preformed channelstrip 20. The pitch of the guideway depends upon the desired advance cfthe channel 'striplil.

To guide the -:opposite side of the channel strip. a spiral guidingmember or r ib 3 5 is affixed :at :one e'ndby a screw 3-! upon-anextension- 240f :the guide block til, thesur face of the extension beinghorizontal and-substantially tangential to the top of the 'mandrelell.After the guide'rib 35 :has

"wound about one and one quarter turns :around the mandrel, itterminates. .Starting :from the center line-ofthe mandrel at the top,:its leading edge tapers toward the trailing edge to :such extentthat'the guide would :terminatein a point if continued to the point ofcontact of the pressure rolls with the channel strip. .However, .so asto avoid a weak end-point, 'Zthe guide .rib :is trunca'ted betweensaidpointand the top nf-theimandr'el. The-effect of this tapering of theguiderib 35 is to guide the movement of the third convolution of thepreformed metal strip over .next to the second convolution, ashereinafter will .be more fully-described.

In order to inserta-strip FS of cloth or fabric or other flexiblematerial, .a guide member designated generally by the numeral 10 isfixedly positioned above the ma-n'dre'l lby a supporting by bolts 8i.

bracket 12 which may be attached to a fixed part (not shown) of themachine. This cloth guide is generally of inverted channel form,converging at its end portion over the top of the mandrel, as will bedescribed. The fabric guide is or may be curved upwardly toward theentrance end. At the entrance end the guide has side flanges I I, 13substantially perpendicular to the roof of the guide and extendingdownwardly. As the guide proceeds toward the exit end, the flange IIcarrying the forward edge of the fabric is bent into an acute angle orcurved reversely toward the mandrel so as to tuck the fabric under thetrailing edge of the second convolution of the metal strip on themandrel. The opposite flange 13 of the guide, which carries the trailingedge of the fabric strip, is or may be bent into an oblique angle orcurved on a radius outwardly so as to tuck the trailing edge of thefabric strip FS-under the trailing flange 22 of the metal strip 20 atabout the point where the metal strip enters the spiral guideway 42 ofthe guide block 40.

Sometimes it is desirable that the fabric guide 10 be provided with abottom wall. It may be in the form of a strip of sheet metal 15 weldedto the edges of the guides flanges II, 13. At about the point where theguide starts to converge to the exit end, an extension 16 which is ormay be relatively springy, is secured to or made integral with anextension of the bottom 15.

With the cloth inserted in the first and second convolutions of themetal channel strip 20, the trailing edge of the second convolution willhave two layers of fabric under its flange. In that condition the fabricstrip and the metal channel are fed around the mandrel to the first orbending roll 90.

Referring to Figs. 7 to 10, support for the bending and pinching rollsis afiorded by a cast head 52 which is formed with a vertical flat face53, bearing against a flat vertical face on a standard 60 on which it isadjustably secured The standard 60 may be a casting having a horizontalportion 65 resting on and secured to the machine frame II in a suitablemanner.

Formed integral with the head 52 are parallel side members 52a and 52bwhich project forwardly from the'head 52 at opposite sides of thestandard 60 and are provided with horizontal parallel open slots inwhich are movably mounted the ends of a rectangular shaft housing 66.Journalled in the housing 66 is a shaft 68 which projects from both endsof the housing and has aflixed on one end thereof a drive gear 69. Onthe other end is mounted the pinching roll 45 which adjustably carriesthe bending roll 90. The gear 69 is driven by suitable driving mechanismwhich is or may be similar to that illustrated in the application of A.E. Chernack S. N. 705,039, filed October 23, 1946, now Patent 2,539,814.

The shaft housing 66 is provided with a vertical circular opening, inwhich is mounted an annular bushing 18, having snugly fitted therein thecylindrical lower end of a pin 19. The pin 19 has a flattened bodyportion snugly fitting in slot 80 in the upper portion of the sidemember 5212. At its upper end the pin 19 is attached to a plate 8| whichbears upon the top surface of the side member 521) and is adjustablysecured thereto. The adjustment is accomplished by bolts 82 extendingthrough slots 83 in the plate 8i and engaging in threaded openings inthe upper portion of the side member 52b. This method of securing theshaft housing 66 permits of adjusting the main shaft housing in thehorizontal slots in the side members 52a, 52b and also permits of apivotal movement of the housing about the lower cylindrical end of thepin 19 as an axis.

Aifixed by bolts and pins 841) to the shaft housing 66 is aspring-bearing bracket 84. The bracket 84 has a circular bore for a coilcompression spring 81. The opposite end of this spring and its shank ishoused in a spring-housing member 86 which may be ailixed to the sidemember 52a in any suitable fashion and may have an adjustment screw 88for varying the tension of the spring.

In this manner the pressure of the whole pinching roll assembly againstthe mandrel, more particularly against the metallic strip member of thetubing, can be regulated.

The bending and pinching rolls 90 and 45 are side by side. Roll 45 ismounted upon the rotating shaft 68 whose axis is parallel to the axis ofthe mandrel and roll 90 is driven by roll 45 as more fully describedbelow. The axis of the roll shaft 68 is or may be at about the samelevel as the axis of the mandrel, the details of the mounting rollsbeing described in detail below. 7

The roll 45 has a hub 41 mounted upon the .shaft 68 and keyed thereto bya key 48, a nut '49 on the threaded end of the shaft serving to hold theroll in place.

The roll 90 is mounted upon a mounting bracket designated generally bythe numeral I00. The bracket I00 has a U-shaped portion with arms IOI,I02 embracing the end portion of the shaft housing 66. In this portionof the housing 66 are grooves or guideways 66g which are parallel andlocated on opposite sides of the housing 66. Into these guideways extendguide pins I04 so as to guide the movement of the bracket I00 relativeto the housing. To secure the bracket I00 in the desired adjustedposition, set screws I03 extending through the arms of the bracket intothe guideways are provided. Extending toward the end of the shaft 68from the U-portion of the bracket I00 is a bearing portion having aflange part I06 from which extends a sleeve part I0I. These parts I06and I0! may, if desired, be a separate member bolted to the U-portion ofbracket I00. A hub portion ofthe roll 90 is mounted upon the sleeveportion I01 on the bracket member I00, there being provided a bearing 96therebetween.

In order to drive the roll 90 from the roll 45, a pin 91 is mounted inthe roll 90 and extends laterally therefrom into an elongated radialslot in the roll 45. Thus as the roll 45 is turned by its shaft 68, itcarries with it by reason of the pin and slot connection 46, 91, theroll 90 which thus revolves on the sleeve portion III! of the bracket.

For the purpose of adjusting the roll 90 relative to the roll 45, theinternal diameter ofthe bracket sleeve I01 is greater than the hub 41 ofthe roller 45. An adjustment bolt H0 is mounted in an extension or arm84a of the spring support member 84. This adjustment bolt extendsthrough the transverse part of the bracket member I00 in a sliding fit.For that purpose the end portion of the bolt I I0 may be of reducedsection and without screw threads. A diametrical pin H2 is provided inthe end of the escapee inside surface of the bracket I to move thebracket in one direction. Upon rotation of the adjustment bolt H0 in theother direction, the shoulder formed at the reduction of the end portionof the adjustment bolt will engage the outer side of the bracket to movethe bracket in the other direction.

The first or bending" roll '90 has two circumferential surfaces 91. 92,one '(-9I being of less diameter than theother "(-92). The'first surface#91 ni'erely bends the trailing edge 22 of the second convolution of themetal strip 'downward'but does not pinch it as tightly as .possible. Itbends the trailing edge merely to hold the fabric'edges under thetrailing flange. The second surface 92 of the first pressure roll actsupon the forward edge 2| of the metal strip and pinches the forwardflange down tightly against the body of the strp. Adjustment of thisroll by the means above described enables surfaces 9| and 92 to beproperly located relative to the second pressure roll 45.

The second pressure roll 45 has but one cir- 'cumferential surface. Itacts upon the trailing flange of the metallic strip in the thirdconvolution and pinches it down tightly to hold the fabric between thebody of the strip and the underside of the flange 22. w

By reason of the tapering of the forward edge of the guide rib 35, thethird convolution of the metal strip is guided by said edge as the stripis moved toward the second convolution (as illustrated best in Fig. 6)by the back pressure of the roll 45. acting on the metal strip as itpresses thereon.

The movement of the third convolution toward the second causes a foldingof excess fabric over the forward edge 2| of the metal strip in thethird convolution. Thus when the second pressure Iroll acts upon thethird convolution to press down or pinch the trailing edge of the metalstrip, it will at the same time pinch this folded fabric. As a result ofthis pinching, the fabric will always tend to fold outwardly when thefinished tube is expanded and compressed.

In the foregoing description and in Figs. 1 to 6 of the drawings,certain of the parts have been shown enlarged for the sake'of clarity,the invention being more readily understandable with such parts as themetallic strip 20., the guide 35 and the fabric strip FS enlarged, thanif said parts were shown in exact proportion to the other parts of themachine as they appear in actual practice.

-It is also possible to form the bending and pinching rolls as a unit,though under such conditlons the adjustability of the surfaces of theroll is surrendered. A unitary roll is illustrated in Fig. 11, whereinsimilar reference numerals are applied to similar parts. The rollismounted on the'shaft B8 and caused'to turn therewith by 'akey. Thecircumferential surfaces ii and I92 acting on the second convolution ofthe metal strip like the surfaces 9|, 92 of the previously describedroll 98 and the circumferential surface 145 acting on the thirdconvolution like the surface of the previously-described roll 45.

It may sometimes be desirable to tuck, a reversely folded forward edgeof the fabric under the trailing edge of the second convolution of themetal strip as illustrated in Fig. 12 to more securely hold the fabricedges. Hence the invention is hot limited to tucking a singlethickhess-edge, nor a double reversely folded edge;

neither is it limited to a metal strip having a reversely-bent fla'n'ge2| on its forward edge, since said flange may. if desired, be omitted.The invention may also be applied to a preformed metalstrip having itstrailing edge serrated as disclosed in my co-pending application, S. N.78,-135 entitled "Collapsible Tubing" flle'd February 24, 1949, issuedconcurrently herewith and claiming tubing of the sort described herein.

Mariy modiflcatlons of this invention will octo those skilled in theart. Therefore I do not limit it to the specific embodiments shown anddescribed.

What is claimedls: l. The method of -forming collapsible tubingcomprising forming 'aspiralled convolution from a preformed strip ofmetal having at least "one edge bent to form a flange, inserting oneedge of a strip of flexible material under one flange of said metalstrip during the formation of said convolution, inserting the other edgeof said flexible strip under said one fla'nge during "the formation of asucceeding convolution, and pressing down said one flange of themetal-strip on the inserted edges of the flexible strip.

2. The method of forming collapsible tubing comprising-forming aspiralled convolution from a preformed strip of metal having its edgesbent to form flanges, inserting one edge of a strip of flexible materialunder one of -the edge flanges of said metal strip during the formationof said convolution, inserting the other edge of said flexible stripunder said one flange during the formation of a succeeding convolution,pressing of said metal strip.

'3. The method of forming collapsible tubing comprising forming aspiralled convolution from a preformed strip of metal having its edgesbent to form flanges, inserting one edge of "a strip of flexiblematerial under one of the edge flanges of said metal strip during theformation of said convolution, inserting the other edge of said flexbiestrip-under said one "flange during the formation of a succeedingconvolution, and pressing down the other flange of said metalstripsimultaneously with the pressing down of said one 4. The method offorming collapsible tubing comprising forming a spiralled convolutionfrom a preformed strip of metal having "at least -one edge bent to forma flange ,'insertin'g one edge of a strip of flexible material under oneflange of said metal strip during the formation of said c i'on'volution,folding over'the other edge of said flexible strip upon itself andinserting said folded edge over the flexible strip and under said oneflange during the formation of a succeeding cohvolution, and pressingdown said one flange of the metal strip on the inserted edges of theflex-ie a 5. The method of forming collapsible tubing comprising forminga spiralled convolution from a preformed strip of metal having its edgesbent to form flanges, inserting one edge of a strip of flexible materialunder one of the edge flanges of said metal strip during the formationof said convolution, folding over the other edge 'of said flexible stripupon itself and inserting said folded edge under said one of the flangesduring the formation of a succeeding convolution, and pressmg down saidone of the ilanges or the metal strip 1 on the inserted edges of theflexible strip, and simultaneously with the pressing down of said .oneof the flanges of the metal strip, pressin down the other flange of saidmetal strip.

6. The method of forming collapsible tubing comprising forming aspiralled convolution from a preformed strip of metal having at leastone edge bent to form a flange, inserting one edge of a strip offlexible material under one flange of said metal strip during theformation, of said convolution, inserting the other edge of saidflexible strip under the same flange of said metallic strip as thefirst-mentioned edge of the flexible strip during the formation of asucceeding convolution, and pressing down said same flange of the metalstrip on the-inserted edges of the flexible strip to hold them duringthe formation of said succeeding convolution, and pinching said sameflange onto said edges of the fabric strip on forming a thirdconvolution.

7. The method of forming collapsible tubing comprising forming aspiralled convolution from a preformed strip of metal having at leastone edge bent to form a flange, inserting one edge of a strip offlexible material under one of the edge flanges of said metal stripduring the formation of said convolution, inserting the other edge of,said flexible strip under the same flange of said metallic strip as thefirst-mentioned edge of the flexible strip during the formation of asucceeding convolution, creating outside the tubing a folded excess ofmaterial of said flexible strip between said first formed convolutionand the succeeding convolution while advancing them,

and pinching said fold, and pressing down said same flange of the metalstrip on the inserted edges of the flexible strip.

8. The method of forming collapsible tubing comprising forming aspiralled convolution from a preformed strip of metal having at leastone edge bent to form a flange, inserting one edge of a strip offlexible material under one of the edge flanges of said metal stripduring the formation of said convolution, inserting the other edge ofsaid flexible strip under the same flange of said metallic strip as thefirst-mentioned edge of the flexible strip during the formation of asucceeding convolution, and creating outside the tubing a folded excessof material of said flexible strip between said first formed convolutionand the succeeding convolution while advancing them, and pinching saidfold while pressing down said same flange of the metal strip on to theinserted edges of the flexible strip.

9. The method of forming collapsible tubing comprising forming aspiralled convolution from -a preformed strip 'of metal having at leastone edge bent to form a flange, tucking the opposite edges of a flexiblestrip under the flange of the trailing edge of the metal strip inadjacent convolutions, folding over excess material of said fabric stripon the outside of the tubing and pinching the fold of said excess andsimultaneously bending said trailing edge flange to secure the edges ofsaid flexible strip to said metal strip.

. 10. The method of forming collapsible tubing tions, folding saidexcess, and pinching said fold while bending said trailing edge flangeto secure the edges of said flexible strip to said metal strip.

11. In a machine for forming collapsible tubing from a preformed stripof metal having at least one edge bent to form a flange, means to formsaid metal strip into successive spiralled convolutions, means to insertthe trailing edge of a flexible strip under the trailing flange of themetal strip in one convolution, means to insert the forward edge of theflexible strip under the trailing edge flange of the metal strip in asecond convolution, and means to press said trailing flange onto theinserted edges of flexible strip in said second convolution.

12. A machine as claimed in claim 11 wherein said pressing of theflanges serves to temporarily hold the flexible strip, and means topinch down said flange and firmly secure said flexible strip edgesduring the formation of a third convolution.

13. A machine as claimed in claim 11 wherein the means to form spiralledconvolutions comprises a rotary mandrel, and stationary means to guidethe metal strip during the formation of the convolutions in the courseof forming the tubing, one of said guide means serving to guide oneconvolution toward another.

14. A machine as claimed in claim 11 having means to guide oneconvolution toward a succeeding convolution creating an excess of foldedmaterial of said flexible strip therebetween on the outside of the tube,and means to pinch the fold.

15. A machine as claimed in claim 11 having means to guide oneconvolution toward a, succeeding convolution creating an excess offolded material of said flexible strip therebetween on the outside ofthe tube, and means to pinch the fold and simultaneously to press downsaid trailing flange onto the inserted edges of the flexible strip.

16. In a machine for forming collapsible tubing from a preformed stripof metal having at least one edge bent to form a flange, means to formsaid metal strip into successive spiralled convolutions, means to insertthe trailing edge of a flexible strip under the trailing flange of themetal strip in one convolution, means to insert the forward edge of theflexible strip in a second convolution, and means to bend down saidtrailing flange to hold the edges of the flexible strip during formationof a second convolution, means to guide toward the second convolutionthe metallic strip as it advances thus creating an excess of foldedmaterial of said flexible strip outside the tubing, and means to pinchthe fold and to pinch down the flange to securely hold the edges of theflexible strip. I I i 17. In a machine for forming collapsible tubingfrom a preformed strip of metal having at least one edge bent to form aflange, means to form said metal strip into successive spiralledconvolutions, means to insert the trailing edge of a flexible stripimder the trailing flange of the metal strip in one convolution, meansto insert the forward edge of the flexible strip under the trailing edgeflange of the metal strip in a second convolution, means to bend downsaid trailing flange to hold the edges of the flexible strip duringformation of said second convolution, and means thereafter to firmlypress down the flange and permanently secure the edges of the flexiblestrip, and means to adjust the bending means relatively to said pressingmeans.

18. In a machine for forming collapsible tubing from a preformed stripof metal having at least one edge bent to form a flange, means to formsaid metal strip into successive spiralled convolutions, means to insertthe trailing edge of a flexible strip under the trailing flange of themetal strip in one convolution, means to insert the forward edge of theflexible strip under the trailing edge flange of the metal strip in asecond convolution, means to bend down said trailing flange to hold theedges of the flexible strip during formation of said second convolution,and means to thereafter firmly press down the flange and permanentlysecure the edges of the flexible strip, and means to adjust the bendingmeans relatively to said pressing means, said bending means being drivenby said pressing means.

19. A machine as claimed in claim 18 having means to adjust the bendingmeans relatively to said pressing means.

20. In a machine for forming collapsible tubing from a preformed stripof metal having opposite edges bent to form flanges, means to form saidmetal strip into successive spiralled convolutions, means to insert thetrailing edge of a flexible strip under the trailing flange of the metalstrip in one convolution, means to insert the forward edge of theflexible strip under the trailing edge flange of the metal strip in asecond convolution, and means to press said trailing flange onto theinserted edges of flexible strip in said second convolution, and meansto press down fully the forward flange of the metal strip during theformation of second convolution.

21. In a machine for forming collapsible tubing from a preformed stripof metal having opposite edges bent to form flanges, means to form saidmetal strip into successive spiralled convolutions, means to insert thetrailing edge of a flexible .strip under the trailing flange of themetal strip in one convolution, means to insert the forward edge of theflexible strip under the trailing edge flange of the metal strip in asecond convolution, and means to press said trailing flange onto theinserted edges of flexible strip in said second convolution, and meansto press down said trailing flange to hold the inserted edges of theflexible strip during the formation of the second convolution andsimultaneously to pinch down fully the forward flange of the metalstrip.

22. In a machine for forming collapsible tubing from a preformed stripof metal having opposite edges bent to form flanges, means to form saidmetal strip into successive spiralled convolutions, means to insert thetrailing edge of a flexible strip under the trailing flange of the metalstrip in one convolution, means to insert the forward edge of theflexible strip under the trailing edge flange of the metal strip in asecond convolution, and means to press said trailing flange onto theinserted edges of flexible strip in said second convolution, and meansto press down said trailing flange to hold the inserted edges of theflexible strip during the formation of the second convolution andsimultaneously to pinch down fully the forward flange of the metalstrip, and means to pinch down fullv said trailing flange duringformation of a third convolution. I

23. A machine as claimed in claim,21 having means for forming a fold ofexcess material of said flexible strips outside the tubing, and means topinch the fold.

24. A machine as claimed in claim 21 having means to form a fold ofexcess material of said flexible strip outside the, tubing, and means topinch the fold while pinching down fully said trailing flange duringformation of a third convolution.

25. In a machine as claimed in claim 11 having means to fold overoutside the tubing excess material of the flexible strip betweenconvolutions, and means to pinch the fold.

26. A machine as claimed in claim 25 wherein rotating roll means havingdifferent circumferential surfaces causes the bending of the flange andthe pinching of thefolded material.

27. A machine as claimed in claim 11 wherein the means to insert theflexible strip comprises a flattened tubular member having convergingtoward its exit end, said exit end having its trailing and forward edgesextending obliquely and reversely bent, respectively.

28. A machine as claimed in claim 27 wherein the tubular member has aspring finger near its exit end in extension fromthe bottom portion ofsaid member, to guide the outflow of the flex ible strip therefrom.

29. A machine as claimed in claim 11 wherein the means to form the metalstrip in the spiralled convolutions comprises a rotary mandrel,stationary means to guide-the metal strip on forming the firstconvolution, and a stationary member spiralled around the mandrel andtapering so as to guide the movement of one convolution toward another.

30. In a machine for forming collapsible tubing from a preformed stripof metal having at least one edge bent to form a flange, means to formsaid metal strip into successive spiralled convolutions, means to insertthe trailing edge of a flexible strip under the training flange of themetal strip in one convolution, means toinsert the forward edge of theflexible strip under the trailing edge flange of the metal strip in asecond convolution, and means to press said trailing flange onto theinserted edges of flexible strip in said second convolution, means tofold over outside the tubing excess material of the flexible stripsbetween adjacent convolutions after said pressing, and means to pinchthe fold, said means to form spiralled convolutions and said foldformingmeans comprising a rotary mandrel, stationary means to guide the metalstrip on forming the first convolution and a stationary member spiralledaround the mandrel and tapering so as to guide the movement 'of oneconvolution toward another.

WILLIAM E. REJESKI.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,580,760 Palmer Apr. 13, 19262,539,814 Chernack Jan. 30, 1951

